The invention disclosed herein relates to a storage module or system having storage elements or storage ranges at least one of which is movable so as to open and close at least one access aisle adjacent a storage range, and in particular to providing aisle safety in such a storage system to prevent an aisle from being closed when a person is in the aisle.
Copending U.S. patent application Ser. No. 07/505,248, filed Apr. 3, 1990, entitled "AUTOMATIC LOCKING DEVICE FOR MOVABLE SHELVING", copending U.S. patent application Ser. No. 07/589,322, filed Sep. 27, 1990, entitled "MOBILE SHELVING SAFETY FLOOR", U.S. Pat. Nos. 4,033,649, 4,412,772 and 4,422,816 (all Naito et al.) and U.S. Pat. No. 4,256,355 (Yamaguchi et al.) describe mobile shelving systems employing movable storage ranges in the form of wheeled carriages supporting storage shelving or racks. The carriages ride on rails so as to be movable to open aisles in which a person may enter to access stored items on the carriage or carriages adjacent an open aisle. The disclosures of patent application Ser. Nos. 07/505,248 and 07/589,322 and the disclosures of U.S. Pat. Nos. 4,033,649, 4,412,772, 4,422,816 and 4,256,355 are hereby incorporated herein by reference.
Mobile storage systems of the type disclosed in those patent applications and patents may employ a control system having user operable controls located at the entrance to each aisle for activating and/or controlling the mechanical arrangements or motors that move the ranges. Such mobile storage systems may also include apparatus connected therein and cooperating therewith to prevent or stop aisle closing movement of a storage range when a person is present in an open aisle. For example, the Naito et al. '772 and '649 patents, the Yamaguchi et al. '355 patent and said U.S. patent application Ser. No. 07/505,248 disclose mobile storage systems comprising a manually-activated control or device at the end of each storage range which when activated cause a range or ranges adjacent an open aisle to be locked. However, such range locking is not failsafe and may be overridden mistakenly by a person who is unaware that another person may be in the open aisle.
U.S. Pat. No. 3,957,323 (Tucker et al.) and the Naito et al. '772 and '649 patents disclose mobile storage systems which include safety bars connected in and cooperating with the storage system to stop movement of a range when a bar contacts an object or a person. However, safety devices such as those safety bars which are connected to stop movement of a storage range after the range has started closing the aisle have the disadvantage that the closing movement of the range may frighten a person in the open aisle.
U.S. Pat. No. 4,744,307 (Peterman et al.), the Tucker et al. '323 patent and said application Ser. No. 07/589,322 disclose switches for mobile storage systems activated by depression of a movable floor section in an open aisle by a person standing on the floor section. The switches are connected in and cooperate with the mobile storage system such that activation of a switch associated with a movable floor section in an open aisle prevents a storage range from closing the open aisle in which the person is standing. However, providing this type of aisle safety requires a raised safety floor, which adds to the cost of the mobile storage system and the installation cost, and which reduces the usable height in the storage area which can be a serious problem in storage areas with limited ceiling height.
U.S. Pat. No. 4,783,618 (Artrip) discloses a mobile storage system comprising a beam radiator and a beam detector located at the entrance of an aisle which are connected in and cooperate with the storage system to prevent an aisle from being closed depending upon the sequence in which radiation is detected. However, devices of that type may nonetheless frequently permit a storage range to commence closing an aisle when a person is present in the aisle. Storage ranges in systems of that type may contain various mechanisms and controls located on the range a convenient height above the floor at the aisle entrance so that mounting the beam radiator and detector at the same convenient height and location as other mechanisms and controls on the range at the aisle entrance may present a space allocation problem.